PCB DFM Review Sign-Off Process

The design owner should approve any fabrication exception that changes product requirements; the fabricator should confirm the proposed process is feasible, and the buyer should confirm commercial consequences. Record these decisions against the exact board revision before authorizing manufacture. A purchasing acknowledgement, a clean automated DFM report and a technical approval are different records. Define which one actually releases your order.

This guide addresses approval of fabrication exceptions, from the first engineering query to the released CAM package. It does not replace a complete design review. Start with the PCB quotation file checklist so the review concerns a complete, identifiable dataset.

Give each query a requirement owner

A supplier can explain that a proposed modification improves manufacturability without knowing whether it changes a connector fit, a calibrated impedance or a safety requirement. The person receiving the email should therefore route the question to the owner of the affected requirement. That owner may be the layout engineer for ordinary copper geometry, a mechanical engineer for a mounting interface, or the responsible product engineer for a system requirement.

The buyer coordinates the answer and records any change in price, quantity or delivery. This is useful even when one person performs several roles. Name the role in the log so a future reviewer understands whether approval covered electrical behavior, manufacturing feasibility or the purchase order.

The table is a proposed organization method, not a prescribed standard. Your company may use different titles or require customer authorization. Establish that authority before the order reaches a time-sensitive hold. An engineer’s availability does not automatically give that engineer authority to waive a customer requirement.

Separate a proposed repair from an accepted change

Eurocircuits describes an optional pre-production approval in its ordering workflow. Its Visualizer guidance also describes proposed repairs that designers can review and approve. These are examples of one supplier’s system. Confirm the equivalent hold and approval behavior with the fabricator handling your project.

Ask whether an unanswered query blocks manufacture, whether a portal approval applies to all open queries, and whether revised data replace or supplement the previous upload. Put the agreed behavior in the order record. An approval button is useful only when its scope is clear to both parties.

For every proposal, capture the original feature and the proposed final feature. Include the layer, coordinates or component references; a screenshot alone may be hard to locate later. State whether the proposal changes the delivered requirement or merely documents how an unchanged requirement will be manufactured. This distinction prevents process information from quietly becoming a design concession.

Write a decision that another engineer can reconstruct

A good approval identifies the query, the affected files, the accepted option and any limits. Avoid replies such as “looks fine” to a long email chain containing several alternatives. A decision can be short while still being specific: “Accept option B for EQ-07 on revision C only; update the fabrication drawing and return the final hole report before release.”

Include a reason when it prevents misunderstanding. For example, a hole change may be acceptable because it remains inside the released finished-hole limits, while a seemingly similar change on another connector is prohibited. Store both decisions. They explain why a global CAM adjustment would be inappropriate.

Illustrative before/after instruction: the original drawing says “Supplier may adjust small holes.” An improved project instruction says “H1 connector holes shall retain the specified finished dimensions. Changes to via group V1 require written approval referencing this drawing revision.” This invented wording demonstrates clearer ownership; the actual dimensions and permitted adjustments must come from the design.

Use a small engineering-query log

Illustrative query record: EQ-07 concerns a proposed enlargement of a via pad on layer L3. The supplier attaches the before/after view, identifies the unchanged net connection, and flags a nearby clearance. The layout owner checks the neighboring geometry and requests a revised proposal. The buyer records that manufacture remains on hold. The second proposal is approved, the CAM package is returned, and the layout owner verifies that the agreed change appears only at the identified features.

The record should contain an issue date, originator, board revision, requirement affected, proposed options, assigned owner, decision, supporting attachment and closure check. Add a status that distinguishes “answered” from “implemented and verified.” A supplier can receive a correct answer yet implement an older option accidentally; the closure check catches that gap.

Do not let the log become the only place a permanent design change exists. If a change should apply to future builds, incorporate it into the controlled CAD or drawing release. If it is a one-lot deviation, identify the permitted lot or quantity and its expiry condition. Otherwise a later reorder may repeat an exception that the design owner intended to be temporary.

Release one coherent manufacturing package

Use the following gate after the technical discussions finish:

1. Confirm that every open query has an assigned owner and a recorded disposition.
2. Check that rejected proposals do not appear in the final CAM or drawing set.
3. List the exact approved files, revisions and supplier processing version.
4. Reconcile construction changes with the approved stack-up drawing.
5. Record commercial effects and obtain the buyer’s acknowledgement where required.
6. Confirm the requested inspection and test records against the quality evidence requirements.
7. Send an explicit release instruction identifying the approved package and order.

A file checksum can help distinguish identically named archives, but it does not prove engineering correctness. Keep it beside the human-readable revision and approval record. For a split shipment or partial build, identify which boards may proceed and which remain held; avoid a broad release statement that could cover both.

If a late change arrives after release, first establish what stage production has reached. Review the consequences for work already performed, revised files and traceability before issuing another release. The fabrication process overview helps the team discuss which operations are affected without assuming that every change can be applied at any stage.